3Lecture 3Diversity of life and prokaryotes9 September 2010BIOL 111 – Organismal Biology4During which geological era did prokaryotes first appear?4%67%19%10%1. Cenozoic?2. Paleozoic?3. Precambrian?4. Mesozoic?

5Lecture outline•Diversityoflife– What is diversity?–How is diversity measured?– Which groups show the greatest diversity?•Prokaryotes–prokaryotes vseukaryotes–cell structure & morphology–3 challenges of life6What is diversity?iofli•BiodiDegree of differences in:1) Genetic variation2) Species composition3) Interactions within and between ecosystemsThis is commonly reserved for indices that measure both the number of species in a habitat as well as their relative abundances•Speciesdi

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7How many species of life exist on Earth today? 1000001 million10 million100 million1 billion2%4%27%41%26%1. 100,0002. 1 million3. 10 million4. 100 million5. 1 billionSome info to ponder….•About1.5millionspeciesarealready namedbout13,000newspeciesnamed each year•But3,000aresynonyms(duplicated species)•TerryErwin1983,treefogging– In one species of tropical tree found 160 beetle speciesunique to that tree species, about 50,000 tropical tree species, beetles are about 2/5 of insects which are about ½of all speciesDiscuss with your neighbour – How many species on Earth today?

9How many species of life exist on Earth today? 1000001 million10 million100 million1 billion1%2%9%31%57%1. 100,0002. 1 million3. 10 million4. 100 million5. 1 billionAccording to May 2002, taxonomists estimate…• 3 – 100 million extant eukaryotic species (May’s guess: 7 million)•BacteriaandArchaeanumberscompletelyunknown (e.g. ~10,000 bacteria species identified but could easily be millions – 100s of millions)•~99% of all species are extinct!

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